For many applications for flexible hoses of plastic materials it is desirable that the hose be of multi-layer construction with at least some of the layers firmly bonded to each other. For example, the hose may have a core tube of a plastic material such as polyamide, polyester, polyurethane, polyvinyl chloride, or the like, with a reinforcement of plastic yarn, such as polyamide or polyester, applied thereto either by braiding, spiral wrapping or knitting. The reinforcement may or may not be covered with a sheath made from the same group of plastic materials from which the core tube may be made. When only a reinforcement is applied to the core tube, it may be desirable to bond the reinforcement to the core tube. If a sheath is also applied, it may be desirable to bond the reinforcement to either or both the core and sheath. In other hose constructions the reinforcement may be omitted and only a sheath applied and bonded to the core tube.
In hoses of the types described, many methods and adhesive materials have been used for obtaining a bond between adjacent layers. However, such methods and materials have not always been satisfactory from the standpoint of bond strength, ease of manufacture and/or safety to manufacturing personnel.